LXR linux/drivers/mtd/chips/map

   1/*
   2 * Common code to handle map devices which are simple ROM
   3 * (C) 2000 Red Hat. GPL'd.
   4 */
   5
   6#include <linux/module.h>
   7#include <linux/types.h>
   8#include <linux/kernel.h>
   9#include <asm/io.h>
  10#include <asm/byteorder.h>
  11#include <linux/errno.h>
  12#include <linux/slab.h>
  13#include <linux/init.h>
  14#include <linux/of.h>
  15#include <linux/mtd/mtd.h>
  16#include <linux/mtd/map.h>
  17
  18static int maprom_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *);
  19static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
  20static void maprom_nop (struct mtd_info *);
  21static struct mtd_info *map_rom_probe(struct map_info *map);
  22static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);
  23static unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,
  24                                          unsigned long, unsigned long);
  25
  26static struct mtd_chip_driver maprom_chipdrv = {
  27        .probe  = map_rom_probe,
  28        .name   = "map_rom",
  29        .module = THIS_MODULE
  30};
  31
  32static unsigned int default_erasesize(struct map_info *map)
  33{
  34        const __be32 *erase_size = NULL;
  35
  36        erase_size = of_get_property(map->device_node, "erase-size", NULL);
  37
  38        return !erase_size ? map->size : be32_to_cpu(*erase_size);
  39}
  40
  41static struct mtd_info *map_rom_probe(struct map_info *map)
  42{
  43        struct mtd_info *mtd;
  44
  45        mtd = kzalloc(sizeof(*mtd), GFP_KERNEL);
  46        if (!mtd)
  47                return NULL;
  48
  49        map->fldrv = &maprom_chipdrv;
  50        mtd->priv = map;
  51        mtd->name = map->name;
  52        mtd->type = MTD_ROM;
  53        mtd->size = map->size;
  54        mtd->_get_unmapped_area = maprom_unmapped_area;
  55        mtd->_read = maprom_read;
  56        mtd->_write = maprom_write;
  57        mtd->_sync = maprom_nop;
  58        mtd->_erase = maprom_erase;
  59        mtd->flags = MTD_CAP_ROM;
  60        mtd->erasesize = default_erasesize(map);
  61        mtd->writesize = 1;
  62        mtd->writebufsize = 1;
  63
  64        __module_get(THIS_MODULE);
  65        return mtd;
  66}
  67
  68
  69/*
  70 * Allow NOMMU mmap() to directly map the device (if not NULL)
  71 * - return the address to which the offset maps
  72 * - return -ENOSYS to indicate refusal to do the mapping
  73 */
  74static unsigned long maprom_unmapped_area(struct mtd_info *mtd,
  75                                          unsigned long len,
  76                                          unsigned long offset,
  77                                          unsigned long flags)
  78{
  79        struct map_info *map = mtd->priv;
  80        return (unsigned long) map->virt + offset;
  81}
  82
  83static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)
  84{
  85        struct map_info *map = mtd->priv;
  86
  87        map_copy_from(map, buf, from, len);
  88        *retlen = len;
  89        return 0;
  90}
  91
  92static void maprom_nop(struct mtd_info *mtd)
  93{
  94        /* Nothing to see here */
  95}
  96
  97static int maprom_write (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf)
  98{
  99        return -EROFS;
 100}
 101
 102static int maprom_erase (struct mtd_info *mtd, struct erase_info *info)
 103{
 104        /* We do our best 8) */
 105        return -EROFS;
 106}
 107
 108static int __init map_rom_init(void)
 109{
 110        register_mtd_chip_driver(&maprom_chipdrv);
 111        return 0;
 112}
 113
 114static void __exit map_rom_exit(void)
 115{
 116        unregister_mtd_chip_driver(&maprom_chipdrv);
 117}
 118
 119module_init(map_rom_init);
 120module_exit(map_rom_exit);
 121
 122MODULE_LICENSE("GPL");
 123MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 124MODULE_DESCRIPTION("MTD chip driver for ROM chips");
 125